When I discovered no ending to Ka-Boom, I came up with a couple:
the 2nd ex-wife accidently killed him with a gun - thinking it had blanks. She wanted to scare him into fixing her butt. She knew he and Maryanne were always pranking each other she placed his body in the car just before it blew up thinking no one would discover the bullet wound. An autopsy revealed otherwise and traced the gun to the set where she worked.
This was Dr. Dick's ultimate prank. He staged his death for a second time. He splattered his car and boat with the left over flesh from some of his patients, nothing identifiable but enough to determine it was human. He would have gotten away with it to if it wasn't for his son. As executor of his father's estate he noticed bank transfers to a bank in foreign country under one of his father's aliases. He was able to direct the feds to his father's exact location and restore his mother's riches before his father could declare that he was not dead and reclaim his riches.